Disk drive actuator and method of making same

ABSTRACT

The present invention relates to a laminated actuator assembly and the method for making the actuator assembly. The actuator assembly is intended for use in miniature personal electronic devices, but could be used in any type of disk drive. The actuator is primarily constructed from strong, stiff, lightweight composite materials. The upper and lower planar elements of the actuator assembly, each comprising multiple composite layers, include a forward portion and a rearward portion. A flexure member, typically positioned between the layers of composite material, allows the forward portion of each planar element to pivot in unison relative to the rear portion of each planar element. In this manner, the position of an optical pick up unit or other read/write device positioned at the distal end of the actuator assembly can be adjusted relative to the surface of a data disk. The composite and flexure planar elements are formed in arrays of multiple component pieces with aligned registration members. The registration members provide accurate alignment during assembly. Adhesive is applied in appropriate quantities to fully fill the space between the upper and lower layers, without seepage at the edges. By assembling the actuator components in arrays, the miniature actuator assemblies can be easily handled and the electronic, optic and magnetic subassemblies can be attached more easily.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is related to U.S. patent applicationSer. No. 09/557,284, filed Apr. 24, 2000, entitled “Tilt Focus Methodand Mechanism for an Optical Drive,” which is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to disk drives and, moreparticularly, to laminated actuator assemblies made from compositematerials and the method for making such actuator assemblies.

BACKGROUND OF THE INVENTION

[0003] Disk drives typically write data to or read data from some typeof circular media, such as a magnetic or optical disk. The disk isusually arranged in concentric circles or tracks on the disk. As thedisk rotates about a shaft, data is read from or written to the disk byoperation of a read/write element or head assembly. An actuatorassembly, including an actuator arm, positions the read/write elementover the various tracks for purposes of reading data from or writingdata to designated tracks on the disk.

[0004] It is a continuous goal of the disk drive industry to reduce thesize and weight of disk drives while simultaneously increasing, or atleast maintaining, storage capacity. With reduced size and increasedcapacity, disk drives can be used in an ever increasing variety ofapplications. For example, miniature disk drives not only allow forbuilding smaller portable computers, but also provide enhancedfunctionality to personal electronic devices (PEDs) such as cameras,music players, voice recorders , cam corders, portable music recordersand other similar devices. In this regard, many disk drive components,like actuator assemblies, are being designed as plastic pieces to reduceweight and cost of production compared to metal actuator assemblies.However, plastic actuator assemblies are more susceptible to breakagefrom shock or extreme temperature variations that come with use inportable instruments. Moreover, plastic actuator assemblies also areless rigid and therefore susceptible to vibration and bending which canresult in positioning errors which may lead to track encroachment. Lackof stiffness or rigidity can also create resonant frequency problemsand, as a result, require limitations in the bandwidth of servo systemsin which they operate to avoid such problems.

[0005] Plastic actuator assemblies are also susceptible to imprecisionin molding processes. For example, while filled plastics may haveimproved properties, they also may have irregularities, such asanisotropic properties, which are difficult to control. Similarly, metalactuators are also susceptible to imprecision in manufacture, whether itbe forging, etching or stamping. Such imprecision, even withinacceptable tolerances ranges, may create problems in positioning thehead assembly relative to the disk. Attaining desired degrees ofprecision in the manufacture of actuator assemblies is made even moredifficult as actuator assemblies become smaller and smaller. Controllingmanufacturing tolerances at increasingly smaller sizes in molding,forging, etching or stamping even if attainable, becomes prohibitivelyexpensive.

SUMMARY OF THE INVENTION

[0006] One embodiment of the present invention is a laminated actuatorassembly comprising three or more planar elements, with most of thoseplanar elements comprising carbon fiber composite material made ofseveral layers. These multi-layer carbon fiber composite planar elementsare separated by a central planar element comprising a flexure andspacer. The number of individual layers or plies comprising the planarelements may vary. Fiber orientation among the various carbon fiberlayers is selectively and strategically placed through the thickness ofthe carbon fiber planar element to align with principal axes of the beamelements of the actuator arm in order to optimize particular objectives,such as bending and twisting stiffness.

[0007] One of the planar elements also comprises a flexure member. Theflexure member allows the forward portion of the actuator assembly topivot relative to the rear portion of the actuator assembly, allowing anoptical pick up unit disposed on the distal end of the actuator assemblyto move relative to the surface of an optical disk for purposes ofmaintaining focus on the information layer of the disk. The flexuremember is preferably made from a lightweight, flexible metal having ahigh yield strength and can be formed from either an etching, stampingor die cutting process. The flexure member may be positioned adjacentthe outer surface of a carbon fiber planar element, or it may bepositioned between two carbon fiber planar elements. In those instanceswhen the flexure member is disposed between carbon fiber planarelements, a spacer also may be included to maintain appropriate spacingbetween carbon fiber planar elements directly separated by the flexure.The spacer provides for a more uniform adhesive layer in the completedlaminated actuator assembly. The flexure member footprint does notnecessarily have to match the footprint of the carbon fiber planarelements. Similarly the footprints of the carbon fiber planar elementsmay vary. Such variability facilitates attachment of other components,such as the optical pickup unit and flex circuit.

[0008] The fibers in the various layers of the planar elements need notbe carbon but may be glass or light metals such as boron, magnesium orberyllium, or other materials such as kevlar or ceramic. Alternatively,the fibers in any particular layer may comprise a combination of two ormore of these materials. The spacer may be made of the same material asthe flexure member, or may be made of a laminate of fiber layers such ascarbon or of other lightweight materials, such as magnesium, foam core,plastic or honeycomb. The combination provides a structure which isstrong, light weight and resistant to bending, vibration and twisting,and one which is ideal for use in a miniaturized environment.

[0009] The fiber laminate planar elements provide the structuralcharacteristics of the actuator assembly. These planar elements, orupper and lower composite planar elements when viewed relative to thesurface of the disk, are manufactured in arrays of multiple componentpieces. More specifically, a number of layers of fiber material arecombined to form a composite planar element panel. A water jet or otherappropriate cutting device, under computer control, cuts the compositeplanar element panel into an array of multiple copies of the upper andlower fiber planar elements, still attached to the exterior frame of theoverall lamination panel. For efficiency and handling, the componentpieces remain attached to the overall lamination panel in an arrayformat. In addition, registration points are also formed in each panelfor subsequent use in aligning the panel to the corresponding arrays ofcomponents in mating panels during subsequent processing. The panels offlexure elements include similar registration features for co-alignmentwith the panels of upper and lower carbon fiber planar elements.

[0010] As an alternative, unique or individual cuts may be initiallymade in the composite planar element panels before lamination and allcuts common to the planar elements made following the lamination of theplanar elements. Using appropriate registration features, the individualcomposite planar element panels are laminated to create the laminatedactuator assembly panels. Fabrication in this manner provides the optionto have different footprint geometries of the individual planar elementsor the overall laminate of the actuator assembly, since the componentshape can be unique in each planar element.

[0011] The number of planar elements in the laminated actuator assemblycould range from one, with the flexure on either the top or bottomsurface, to as many as two dozen, with the flexure being located oneither surface or between any two interior planar elements. The numberof fiber layers in a single composite planar element is determined bythe thickness limitations of the planar element, dividing the allowableplanar element thickness by the fiber diameter at maximum materialcondition. Practical embodiments would likely range from one to sevenplanar elements in an actuator assembly. Each planar element can beoptimized for directional stiffness properties via fiber orientation,based upon the final placement within the thickness of the planarelement and the laminated actuator assembly.

[0012] Lamination is accomplished by aligning and bonding multiple fiberlayers to form fiber planar elements, and by aligning and bonding one ormore fiber planar elements to the flexure planar element. As previouslystated, a spacer element may be positioned in a coplanar relationshipwith the flexure planar element. The bonding process may be accomplishedby oven cure or room temperature cure. Pressure is applied to the stackof planar elements during the cure process, via a clamping fixture thatcan be set to establish a finished laminate stack thickness. Setting ofthe stack height effectively defines the bond line thickness dimensionsso that bond strength and adhesive squeeze out can be optimized.Adhesive is applied to the fiber planar elements either prior toalignment and installation in the clamping fixture or as the arrays ofplanar elements are placed in the clamping fixture. Adhesive can beapplied using silk screen techniques, with the silk screen also havingregistration members for accurate alignment with the fiber planarelements. Alternatively, the adhesive may be applied by roller or byspraying or other printing or as a film. The clamping fixture may alsoinclude a vacuum chuck to constrain movement and maintain alignment ofthe planar elements and silk screen pattern. The clamping fixtureincludes complementary registration features which interact with theregistration features in the fiber and flexure planar element panels toaccurately position the planar elements relative to each other.

[0013] In embodiments that utilize a flexure which does not match thefootprint of the mating fiber planar elements, and in which a spacerlayer is not utilized, a varying bond line thickness is created. Inorder to prevent adhesive overflow at the edges of the planar elements,the adhesive cannot be applied in a single, uniformly thick layer. Toovercome this problem, the adhesive is applied in a single applicationof discreet stripes of adhesive, analogous to half tone printingprocedures. In the areas where the flexure is present, fewer or lessdense stripes of adhesives are applied. As a result, when the planarelements are all aligned and appropriate pressure is applied, theadhesive spreads out and uniformly fills the space between the planarelements that encapsulate the flexure member.

[0014] Once arrays of upper and lower fiber planar elements and flexureplanar elements have been laminated into an array of actuator arms, thearms may be removed (singulated) from the laminated panel for furtherassembly operations, or left in the panel and further assemblyoperations performed in panelized, batch process operations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] For a more complete understanding of this invention, one shouldnow refer to the embodiment illustrated in greater detail in theaccompanying drawings and described below by way of example of theinvention. In the drawings:

[0016]FIG. 1 is a top plan view of an embodiment of the actuatorassembly of the present invention.

[0017]FIG. 2 is a top plan view of an embodiment of the actuatorassembly of the present invention, with the optical, magnetic andelectrical components removed.

[0018]FIG. 3 is a side view of the assembly shown in FIG. 2.

[0019]FIG. 4 is an exploded view of the actuator assembly shown in FIG.2.

[0020]FIG. 5 is a partial cut away perspective view of the layers of anupper and lower composite planar element and a composite planar elementpanel of the present invention, showing the orientation of the fibers ineach layer.

[0021]FIG. 6 is a top plan view of an array of lower composite planarelements, further showing the various axes of orientation of the fiberswithin the layers comprising the upper and lower composite planarelements.

[0022]FIG. 7 is a separate top plan view of the forward and rearwardportions of the upper composite planar element of the actuator assemblyshown in FIG. 2.

[0023]FIG. 8 is a separate top plan view of the forward and rearwardportions of the lower composite planar element of the actuator assemblyshown in FIG. 2.

[0024]FIG. 9 is a top plan view of the flexure and spacer of theactuator assembly shown in FIG. 2.

[0025]FIG. 10 is a top plan view of an array of upper composite planarelements of the actuator assembly shown in FIG. 2.

[0026]FIG. 11 is a top plan view of an array of lower composite planarelements of the actuator assembly shown in FIG. 2.

[0027]FIG. 12 is a top plan view of an array of flexure and spacermembers of the actuator assembly shown in FIG. 2.

[0028]FIG. 13 is an elevated perspective view of a vacuum chuck assemblyused in assembling an actuator assembly of the present invention.

[0029]FIG. 14 is a partially exploded view of a vacuum chuck assembly,an array of upper composite planar elements and a silk screen adhesivepattern used in assembling an actuator assembly of the presentinvention.

[0030]FIG. 15 is a top plan view of the glue pattern for a complementarypair of upper and lower composite planar elements.

[0031]FIG. 16 is an exploded view of the lower bonding plate, compositeplanar elements, flexure panel, spacer panel and upper bonding plate,showing the depth stops.

[0032]FIG. 17 is a top view of the bonding fixture.

[0033]FIG. 18 is a cross-section view of the bonding fixture taken alongline 18-18 of FIG. 17.

[0034] While the following disclosure describes the invention inconnection with one embodiment, one should understand the invention isnot limited to this embodiment. Furthermore, one should understand thatthe drawings are not necessarily to scale and that graphic symbols,diagrammatic representatives and fragmentary use, in part, mayillustrate the embodiment. In certain instances, the disclosure may notinclude details which are not necessary for an understanding of thepresent invention such as conventional details of fabrication andassembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035]FIG. 1 shows a first embodiment of the actuator arm 10 of thepresent invention. As generally shown, the actuator arm includes a rearportion 12 and a front portion 14. The front portion 14 is also referredto as a focus arm. A voice coil 16 is positioned between two extensionsor legs 18, 20 formed in the rear portion and cooperate with permanentmagnets, not shown, to form a voice coil motor (VCM) to position theactuator arm 10 relative to the surface of a disk. A bearing cartridge22 is disposed within a circular bore formed between legs 24, 26 of thefront portion 14 and legs 28, 30 of the rear portion 12. An opticalpickup unit 32 for reading information from or writing information to anoptical disk is disposed at the distal end of the focus arm 14. A secondvoice coil motor 34 acts to move the focus arm 14 of the actuator 10 ina direction generally perpendicular to the surface of the disk in orderto maintain the optical pickup unit in focus with the information layercontained on the disk. The actuator arm 10 is discussed in greaterdetail in pending U.S. application Ser. No. 09/557,284, which isincorporated herein by reference. Although the actuator arm is describedin the context of an optical disk drive, it should be understood that itapplies equally to other applications, including but not limited tomagnetic hard disk drives.

[0036] FIGS. 2-4 provide additional views of the actuator arm 10, withthe optical pickup unit, voice coil motor assemblies and bearingcartridge removed. The forward and rearward portions 12, 14 of theactuator arm 10 of the preferred embodiment are each comprised of anupper planar element 36 and a lower planar element 38 with a flexuremember 40 and spacer member 42, comprising a third planar element 44,disposed between the upper and lower planar elements. In the preferredembodiment, as partially illustrated in FIG. 5, both the upper and lowerplanar elements 36, 38 comprise eight separate layers or plies of carbonfiber material L₁-L₈ made from composite planar element panels 58,although the number of layers or plies comprising the overall laminatestructures which are the planar elements 36, 38 may be more or less,provided symmetry about the neutral axis of the planar element isgenerally maintained. In particular, each carbon fiber layer L₁-L₈ ofthe planar elements 36, 38 has a distinct geometry and purpose such thatthe resulting carbon fiber planar element can take advantage of theseparate benefits of the individual layers. In this regard, the fiberswithin each layer are oriented to optimize the purpose of the layer andeach layer can form a uniaxial fiber matrix. For example, fibers areoriented parallel to the orientation of beam elements to provide desiredstiffness and the fibers of different layers cross at high enough angleswith respect to the other individual layers to provide an overalllaminate structure which is stiff in some directions and flexible inothers. Generally, the fibers are parallel to each other within eachcarbon fiber layer L₁-L₈, but the orientation of the fibers from layerto layer in an overall planar element of the actuator assembly may vary.

[0037] In the planar elements having eight carbon fiber layers, thefibers in each layer are approximately 0.002 inches in diameter. Inaddition, in four of the eight layers L₁, L₂, L₇, L₈, the fibers have azero degree orientation, meaning the fibers are aligned parallel to thelongitudinal axis A_(L) of the actuator arm 10 as shown in FIG. 6. Twoof these zero degree oriented layers L₁, L₂, are the upper most layersand two of the zero degree oriented layers L₇, L₈, are the lower mostlayers of the planar elements 36, 38. The fibers in the center fourlayers L₃-L₆, are oriented alternately at plus or minus 29 degreesrelative to the longitudinal axis A_(L). This orientation is shown inFIG. 6 at A₊₂₉ and A⁻²⁹. Twenty-nine degree fiber orientation isselected because it is the orientation of arm segments 24 and 26relative to the long axis of the actuator arm. By orienting the fibersof these layers L₃-L₆ to be parallel to the orientation of arm segments24, 26, these arm segments or beam elements are stiffened with respectto bending. The layers L₁-L₈ are arranged symmetrically by their fiberorientation to avoid curling of the composite planar element panels 58and planar elements 36, 38. The varying fiber orientation of the layersalso gives greater strength to the overall structure and helps reduce oreliminate damage to the planar elements 36,38 during handling andassembly. Also, it is desirable to carefully control the quantity ofresin within each fiber layer L₁-L₈. By matching the thickness of theindividual layers L₁-L₈ as close as possible to the diameter of thefibers, the strength of the laminated layers, and thus the fiber planarelement, increases.

[0038] Carbon is the preferred fiber because it has among the highestratios of stiffness to density. For example, the specific gravity of acarbon fiber planar element is approximately 1.8, very near that ofmagnesium, but will have a Young's modulus of approximately 50 millionpounds per square inch, whereas magnesium has a Young's modulus ofapproximately 7 million pounds per square inch. By way of comparison,steel has a Young's modulus of 30 million pounds per square inch, but aspecific gravity of 7.8. Thus, a carbon fiber planar element isapproximately four times less dense than steel, but is sixty-sevenpercent stiffer.

[0039] Each planar element 36, 38 is comprised of a forward portion anda rear portion to allow the focus arm 14 of the actuator assembly 10 topivot relative to the disk surface. Thus, with reference to FIGS. 4 and7-9, the upper planar element 36 includes a front portion 46 and a rearportion 48 and the lower planar element 38 includes a front portion 50and a rear portion 52.

[0040]FIG. 9 illustrates an individual flexure member 40 and spacer 42and FIG. 12 illustrates an array of flexure members 40 and spacers 42 inpanel forms 62 and 66 respectively. Preferably, the material used tomake the flexures 40 is a flexible metal such as Sandvick 11R51, whichis a 301 series stainless steel having a yield strength of approximately283,000 psi. However, it should be appreciated that the flexures 40 canbe made from any appropriate flexible material that can withstandrepeated bending as the focus arm 14 is adjusted to maintain focus onthe data layer within the disk. Alternatively, the spacer 42 may be madefrom fiber composite material like the upper and lower planar elements36, 38. In addition, the footprint of the spacer 42 may closely matchthat of the forward portions 46, 50 of the upper and lower planarelements 36, 38, respectively, or it may be smaller and have a profiledifferent from the forward portions of the planar elements to reduceweight or provide different stiffness characteristics to the actuatorassembly.

[0041] The flexure members 40, as shown in FIG. 9, include a frontportion 54 and a rear portion 56 which generally match the contour ofthe adjacent areas of the front and rear portions of the upper and lowerplanar elements 36, 38. The rear portion 56 of the flexure includes anaperture 64 to receive a bearing cartridge 22. Importantly, a pair ofnarrow bridges 57 connect the front portion 54 and the rear portion 56and allow the front portion 54 to pivot relative to the rear portion 56.The narrow portion or bridge 57 avoids any glue seepage from theadjacently abutting upper and lower planar elements 36, 38 from alteringthe frequency of the flexure. As a result, the desired response of thebending of the actuator arm is controlled. Absent this narrow bridge 57being present, glue seepage into the area could alter the bendingcharacteristics of flexure 40. Altering the shape of the flexure is moreeasily accomplished than controlling glue seepage. The array of flexuremembers in panel 62, as shown in FIG. 12, is preferably made by a diecutting and coining process, but could be made by etching or any otherprocess known to persons of skill in the art.

[0042] For purposes of manufacture, eight layers or plies of carbonfiber material L₁-L₈, with the fibers preferably substantially orientedat a predetermined angle (see FIGS. 5, 6), are joined together to form asingle carbon fiber laminate or panel 58, as shown in FIG. 5. Arrays ofupper and lower planar elements 36, 38 are cut into the laminated panel58 to form cut panels 78 and 80 (see FIGS. 10, 11). The number ofindividual component pieces to be cut in an array may vary. Theembodiment shown in the drawings have six upper or lower planar elements36, 38 per array. Ideally, a computer or numerically controlled waterjetis used to cut the component footprints in each panel 58. Alternatively,similarly controlled milling machines can cut the array of componentpieces from the panel 58. A water jet, however, is not only faster, butis much more cost effective than milling machines. Where a millingmachine utilizes a cutting tool that wears out and needs regularreplacement, a water jet has no such problem. Moreover, a water jet cancut multiple panels 58, creating multiple copies of cut panels 78 and 80at one time, thereby further increasing output. FIGS. 10 and 11illustrate arrays of six upper and lower planar elements 36, 38 cut intotwo panels 58 of eight laminated carbon fiber layers, respectively. Atthe same time as the water jet, or other methods known and available tothose skilled in the art cut the arrays of upper and lower planarelements 36, 38, registration members, such as holes 60, are also cut inthe panels 58. The purpose for cutting the registration holes 60 at thesame time as the component structural pieces are cut is to reducesubsequent errors in alignment when assembling and bonding the multipleplanar elements into an actuator arm. In this manner, the only error isthat which would result due to the CNC cutting process, but not to thealignment of the planar elements when combined. Alternatively, theindividual layers L₁-L₈ may be separately cut to form arrays ofcomponent pieces and then laminated to form panels 78, 80 of planarelements 36, 38 or uncommon cuts in each layer L₁-L₈ can be madeindividually and all common cuts can be made following lamination of themultiple layers into a single planar element. The process of formingregistration features in each layer would be the same in order toenhance accurate alignment of the individual layers L₁-L₈.

[0043] In general terms, a method of assembling the actuator of thepresent invention will now be described. As illustrated in FIGS. 5 and6, depicting a first embodiment, eight carbon fiber layers L₁-L₈ arecombined to form the upper and lower panels 58, which are then cut tocreate cut panels 78, 80, from which fiber planar elements 36, 38 willresult. Each layer L₁-L₈ is impregnated with epoxy for bonding theindividual layers together. The combined structure is placed in anautoclave under appropriate pressures and temperatures to activate theepoxy and secure the layers L₁-L₈ into a laminate panel 58. Inconnection with the preferred embodiment, the temperature isapproximately 325° F. and the applied pressure is approximately 50pounds per square inch.

[0044] Following the autoclave procedure, the laminated panels 58, arecut, by means of water jet or other appropriate techniques, into anarray of upper and lower carbon fiber planar elements 36, 38 of theactuator arm 10 in panels 78 and 80. Alternatively, the cutting ofcomponent pieces within the individual layers L₁-L₈ may be done prior tobonding the layers together or some of the cut may be made in individuallayers and the remaining cuts are made in the overall laminated panel.At this point, registration features 60 are also accurately located andcut into the panels 78, 80. Similarly, an array of flexures 40 are cutfrom metallic or other appropriately flexible material into a panel 62which will mate with a pair of upper and lower fiber planar panels 78,80. Also, an array of spacers 42 are cut from appropriate material intoa panel 66, which will also mate with the pair of upper and lower fiberplanar panels 78, 80. The flexure and spacer panels 62, 66 also havealigned registration features, such as apertures 60, to match those inthe carbon composite planar panels 78, 80. In the cutting process, anumber of sprues 70 are left between the planar elements 36, 38 and thesurrounding panels 78, 80, as well as between the flexures 40 andspacers 42 and the remaining panels 62 and 66 respectively. Theregistration holes 60 maintain alignment among the panels 62, 66, 78 and80 during further processing. It should be appreciated that othermethods of providing registration among the various panels can be usedinstead. For example, alignment may be achieved by using panel edges orcorners, or by optically detecting identified fiduciaries on the panelor by bearing bores.

[0045] At this point, the panels 62, 66, 78 and 80 are ready to becombined into an actuator arm assembly. The upper and lower carbon fiberpanels 78, 80 containing planar elements 36, 38, are placed on aclamping fixture, such as vacuum chuck 72 (FIG. 13). The registrationpins 74 on the chuck 72 mate with the registration holes 60 in thepanels 78, 80 and properly co-align the panels. Vacuum pressure throughslots 76 hold an upper and lower planar element panels 78, 80 inposition for application of adhesive. Silk screen techniques are thenused to apply adhesive to both the upper and lower fiber planar elementpanels 78, 80. FIG. 14 illustrates a chuck 72 with a lower panel 80 ofplanar elements 38 positioned on registration pins 74 and an upper panel78 of planar elements 36, also intended to be positioned on chuck 72 butelevated from the surface of the chuck 74 for illustration. A silkscreen82, showing the openings for the pattern of adhesive to be applied, isalso shown. The silkscreen also includes registration holes 84 foraligning the silkscreen 82 relative to the panels 78, 80. It should beappreciated however, that other techniques may be utilized to applyadhesive, including but not limited to application by roller, spray,other printing or as a film.

[0046] To simplify the glue application process, in the preferredembodiment, a single thickness of glue or adhesive is applied across theentire length of the upper and lower panels 78, 80 in one application.Care must be taken to accurately place the adhesive away from edges ofthe upper and lower planar elements 36, 38 to avoid adhesive beingsqueezed out along any edges. Yet, it is also necessary to havesufficient adhesive to fill all voids between the upper and lower fiberplanar elements, taking into account the existence of the flexure andspacer. The glue pattern applied to upper and lower planar panels 78, 80is created by silkscreen 82, as shown in FIGS. 14 and 15. The preferredadhesive is a 3M 2214 metal-filled, single-part epoxy. Because thisepoxy cures at approximately 120° C. or higher, the glue can be appliedto the upper and lower planar panels 78, 80 using the silkscreen 82pattern and stored in a cool location without concern that the glue willcure. This allows an inventory of arrays of combined planar elements 36and 38, with adhesive already applied, to be made in advance and beavailable for final assembly as demand requires. Alternatively, if theflexure 40 and spacer 42 do not match the shape of the planar elements36, 38, a different thickness of glue may be applied at locations wherethe flexure and spacer are absent. In this regard, the glue may beapplied in stripes, analogous to half-tone printing processes, ratherthan in a solid, continuous pattern.

[0047] As completed actuators 10 are needed, the planar panels 78, 80,with adhesive-applied as shown in FIGS. 14 and 15, flexure panels 62 andspacer panels 66 can be positioned within bonding plates 90 a and 90 bas shown in FIG. 16 using the registration holes 60 and registrationpins 92. The upper bonding plate 90 a is then placed over thecombination and secured to the lower bonding plate 90 b underappropriate pressure and temperature conditions. As shown in FIGS. 17and 18, the bonding plates include adjustable limit stops 94, whichestablish the spacing between the upper and lower plates, therebyestablishing the thickness of the actuator assembly. The bonding plates90 containing the panels 78, 80, 66 and 62 are placed in an oven forbonding the component pieces into a final laminated structure.Presently, using the 3M epoxy, this process takes approximately twohours in an oven at 150° C. It should be understood that the processparameters can vary, particularly depending upon the epoxy used.

[0048] Once cured, the completed lamination can be removed from thebonding plates, while the individual component pieces remain attached tothe surrounding structure due to the sprues 70. This allows for ease ofhandling without damage to the miniature laminated structures. Itfurther allows the other component pieces, such as the optical pickupunit, flex circuit, voice coil motors and bearing cartridge, to beassembled to the actuator structure with simplicity.

[0049] While various embodiments have been shown and described, it willbe apparent that other modifications, alterations and variations may bemade by or will occur to those skilled in the art to which thisinvention pertains, particularly upon consideration of the foregoingteachings. For example, the number of layers or plies within the fiberplanar elements may vary as may the relative orientation of the fiberswithin each layer. In addition, while carbon fiber composite materialperforms well in this application, other materials such as glass,magnesium, boron, beryllium, Kevlar and ceramics, alone or in variouscombinations may also perform satisfactorily. It is also contemplatedthat the component shapes may be cut from individual layers of material,which layers are subsequently laminated to form a composite panel, orthat the component shapes are cut from the composite panel. It is stillfurther contemplated that the individual layers comprising a planarelement may have varying shapes and sized relative to each other. Theobjective is to achieve a lightweight, but a strong and stiff actuatorassembly. It is therefore contemplated that the present invention is notlimited to the embodiments shown or described in such modifications andother embodiments as incorporate those features which constitute theessential functions of the invention are considered equivalent andwithin the true spirit and scope of the present invention.

What is claimed is:
 1. A method for making an actuator assembly,comprising: a. Forming a first structural member from composite fibermaterial; b. Forming a second structural member from composite fibermaterial; c. Forming a flexure member from flexible material; d.Applying adhesive to said structural members; e. Combining saidstructural members and said flexure member, with said flexure memberdisposed between said first and second structural members.
 2. The methodof claim 1, further comprising forming registration means in each ofsaid structural members and said flexure member.
 3. The method of claim2, wherein the step of combining said structural members and saidflexure member further comprises aligning said registration means foreach of said structural members and said flexure member.
 4. The methodof claim 1, wherein said step of forming a first structural membercomprises forming a plurality of structural members.
 5. The method ofclaim 1, wherein said step of forming a second structural membercomprises forming a plurality of structural members.
 6. The method ofclaim 1, wherein said step of forming a flexure member comprises forminga plurality of flexure members.
 7. The method of claim 1, wherein saidstep of forming said first structural member comprises forming a forwardportion and a rearward portion.
 8. The method of claim 1, wherein saidstep of forming said second structural member comprises forming aforward portion and a rearward portion.
 9. The method of claim 1,wherein said step of forming said flexure member comprises forming aforward portion and a rearward portion.
 10. The method of claim 1,wherein the composite fiber material used to form said structuralmembers includes carbon fiber.
 11. The method of claim 2, wherein thecarbon fibers have a diameter of approximately 0.002 inches.
 12. Themethod of claim 1, wherein the fibers in said composite fiber materialare selected from one or more of the following materials: glass,magnesium, boron, beryllium, Kevlar or ceramic.
 13. The method of claim1, wherein said forming is cutting.
 14. The method of claim 13, whereinsaid cutting is performed by a water jet.
 15. The method of claim 1,further comprising placing the combination of said structural membersand said flexure member under temperature and pressure to set saidadhesive and bond said structural members and said flexure member into alaminated actuator assembly.
 16. The method of claim 1, wherein saidsecond step of combining comprises placing said flexure member betweensaid first and second structural members.
 17. The method of claim 1,wherein said adhesive is applied using silk screen techniques.
 18. Themethod of claim 1, wherein said act of applying adhesive to saidstructural members comprises applying adhesive to all structuralmembers.
 19. The method of claim 3, further comprising placing saidstructural members and said flexure member in a fixture havingcomplementary registration elements that align with and receive saidregistration members associated with said structural members and saidflexure member.
 20. The method of claim 19, wherein said fixturecomprises an upper and lower portion and a stop means to set the spacingbetween said upper and lower portions.
 21. The method of claim 1,wherein said adhesive is applied by spraying.
 22. The method of claim 1,wherein said step of applying adhesive comprises applying a film ofadhesive to said structural members.
 23. The method of claim 1, whereinsaid steps of forming said first and second structural members comprisecombining a plurality of layers of composite fiber material.
 24. Themethod of claim 23, wherein said plurality of layers of composite fibermaterial is eight.
 25. The method of claim 23, wherein the step offorming said structural members further comprises orienting the fiberswithin each layer to optimize the strength and stiffness of saidstructural members.
 26. The method of claim 24, wherein the fibers insaid layers are oriented relative to the longitudinal axis of said firstand second structural members at zero degrees, zero degrees, plus 29degrees, minus 29 degrees, minus 29 degrees, plus 29 degrees, zerodegrees and zero degrees.
 27. The method of claim 1, wherein said stepsof forming said first and second structural members further compriseforming beam elements within said structural members.
 28. The method ofclaim 25, wherein a portion of the fibers forming said first and secondstructural elements are substantially parallel to at least some of saidbeam elements.
 29. The method of claim 1, further comprising forming aspacer member from non-structural material and positioning said spacermember in a co-planar relationship with said flexure member prior tocombining said flexure member with said structural members.
 30. Themethod of claim 29, wherein said step of forming a spacer membercomprises forming a plurality of spacer members.
 31. The method of claim29, further comprising forming registration means in each of saidstructural members, said flexure member and said spacer member.
 32. Themethod of claim 29, wherein said adhesive is applied using silk screentechniques.
 33. The method of claim 29, wherein said act of applyingadhesive to said structural members comprises applying adhesive to allstructural members.
 34. The method of claim 29, wherein said adhesive isapplied by spraying.
 35. The method of claim 29, wherein said step ofapplying adhesive comprises applying a film of adhesive to saidstructural members.
 36. A method for making an actuator assembly,comprising: a. forming a plurality of first structural members; b.forming a plurality of second structural members; c. forming a pluralityof flexure members; d. forming a plurality of spacer members; e.applying adhesive to at least one of said first and second plurality ofstructural members; f. combining said first and second plurality ofstructural members, said plurality of flexure members and said pluralityof spacer members in a fixture; g. applying pressure to the fixture tocompress the plurality of first and second structural members, pluralityof flexure members and plurality of spacer members to a desiredthickness; and h. heating said combination to set said adhesive and bondsaid plurality of first and second structural members, plurality offlexure members and plurality of spacer members.
 37. The method of claim36, wherein said step of forming a first plurality of structural memberscomprises forming structural members with a front and rear portion, andsaid step of forming a plurality of second structural members comprisesforming structural members with a front and rear portion.
 38. The methodof claim 36, wherein said step of applying adhesive comprises placing asilk screen over said at least one of said plurality of structuralmembers and applying adhesive through said silk screen.
 39. The methodof claim 36, wherein said adhesive is applied by a roller.
 40. Themethod of claim 36, wherein said adhesive is applied by spraying. 41.The method of claim 36, wherein said step of forming first and secondstructural members comprises combining a plurality of individual fibercomposite layers.
 42. The method of claim 36, wherein said steps offorming a plurality of first and second structural members comprisesforming each of said structural members from a plurality of layers ofcomposite fiber material.
 43. The method of claim 42, wherein said stepof forming said first and second structural members comprises cuttingsaid layers into desired shapes.
 44. The method of claim 42, whereinsaid fibers are selected from the group comprising carbon, glass,magnesium, boron, beryllium, ceramic and kevlar.
 45. The method of claim36, wherein said steps of forming said first and second structuralmembers comprise combining a plurality of layers of composite fibermaterial.
 46. The method of claim 45, wherein said plurality of layersof composite fiber material is eight.
 47. The method of claim 45,wherein the step of forming said structural members further comprisesorienting the fibers within each layer to optimize the strength andstiffness of said structural members.
 48. The method of claim 47,wherein the fibers in said layers are oriented relative to thelongitudinal axis of said first and second structural members at zerodegrees, zero degrees, plus 29 degrees, minus 29 degrees, minus 29degrees, plus 29 degrees, zero degrees and zero degrees.
 49. The methodof claim 36, wherein said steps of forming said first and secondstructural members further comprise forming beam elements within saidstructural members.
 50. The method of claim 49, wherein said first andsecond structural elements comprise layers of composite fiber materialand said fibers within at least some of said layers are substantiallyparallel to at least some of said beam elements.
 51. The method of claim36, further comprising creating multiple individual actuator armassemblies by separating the individual arm assemblies from the curedand bonded planar panels.
 52. A method for making an actuator assembly,comprising: a. forming a plurality of first structural members in aplanar element panel; b. forming a plurality of second structuralmembers in a planar element panel; c. forming a plurality of flexuremembers in a planar element panel; d. applying adhesive to at least oneof said first and second plurality of structural members in said planarelement panel; e. combining said first and second plurality ofstructural members in said planar element panels and said plurality offlexure members in said planar panel in a fixture; f. applying pressureto the fixture to compress the plurality of first and second structuralmembers in said planar element panels and said plurality of flexuremembers in said planar panels to a desired thickness; and g. heatingsaid combination to cure said adhesive and bond said plurality of firstand second structural members in said planar element panels and saidplurality of flexure members in said planar panels.
 53. The method ofclaim 52, further comprising forming a plurality of spacer members in aplanar panel and combining said panel of spacer members with saidplurality of structural members and said plurality of flexure members.54. The method of claim 53, further comprising forming registrationmeans in said planar element panels of first structural members, secondstructural members, flexure members and spacer members.
 55. The methodof claim 52, wherein said step of forming a first plurality ofstructural members comprises forming structural members with a front andrear portion, and said step of forming a plurality of second structuralmembers comprises forming structural members with a front and rearportion.
 56. The method of claim 52, wherein said step of applyingadhesive comprises placing a silk screen over said at least one of saidplurality of structural members and applying adhesive through said silkscreen.
 57. The method of claim 52, wherein said adhesive is applied bya roller.
 58. The method of claim 52, wherein said adhesive is appliedby spraying.
 59. The method of claim 52, wherein said step of formingfirst and second structural members comprises combining a plurality ofindividual fiber composite layers.
 60. The method of claim 59, whereinsaid step of forming said first and second structural members comprisescutting said layers into desired shapes.
 61. The method of claim 60,wherein said fibers are selected from the group comprising carbon,glass, magnesium, boron, beryllium, ceramic and kevlar.
 62. The methodof claim 53, further comprising creating multiple individual actuatorarm assemblies by separating the individual arm assemblies from thecured and bonded planar panels.
 63. The method of claim 52, wherein saidsteps of forming said first and second structural members comprisecombining a plurality of layers of composite fiber material.
 64. Themethod of claim 63, wherein said plurality of layers of composite fibermaterial is eight.
 65. The method of claim 63, wherein the step offorming said structural members further comprises orienting the fiberswithin each layer to optimize the strength and stiffness of saidstructural members.
 66. The method of claim 64, wherein the fibers insaid layers are oriented relative to the longitudinal axis of said firstand second structural members at zero degrees, zero degrees, plus 29degrees, minus 29 degrees, minus 29 degrees, plus 29 degrees, zerodegrees and zero degrees.
 67. The method of claim 52, wherein said stepsof forming said first and second structural members further compriseforming beam elements within said structural members.
 68. The method ofclaim 65, wherein a portion of the fibers forming said first and secondstructural elements are substantially parallel to at least some of saidbeam elements.
 69. A method for making an actuator assembly, comprising:a. forming a plurality of arrays of first structural elements fromcomposite fiber material; b. forming a plurality of arrays of secondstructural elements from composite fiber material; c. forming aplurality of arrays of flexure elements from flexible material; d.forming a plurality of arrays of spacer elements from non-structuralmaterial; e. combining said plurality of arrays of first structuralelements to form an array of first planar elements; f. combining aplurality of arrays of second structural elements to form an array ofsecond planar elements; g. applying adhesive to said first and secondarrays of planar elements; and h. combining an array of first and secondplanar elements, an array of flexure elements and an array of spacerelements to form an actuator assembly array. i. creating multipleindividual actuator arm assemblies by separating the individual armassemblies from the cured and bonded planar panels.
 70. The method ofclaim 69, further comprising forming registration elements in each ofsaid first and second arrays of planar elements, said array of flexureelements and said array of spacer elements.
 71. The method of claim 69,wherein each step of combining further comprises aligning saidregistration elements.
 72. The method of claim 69, wherein said firststructural elements comprise a forward portion and a rearward portion.73. The method of claim 69, wherein said second structural elementscomprise a forward portion and a rearward portion.
 74. The method ofclaim 69, wherein said flexure members comprise a forward portion and arearward portion.
 75. The method of claim 69, wherein said compositefiber material comprises carbon fiber.
 76. The method of claim 69,wherein said step of forming is cutting.
 77. The method of claim 76,wherein said cutting is performed with a water jet.
 78. The method ofclaim 69, wherein said step of combining an array of first and secondplanar elements, an array of flexure elements and an array of spacerelements comprises placing said arrays of planar elements, flexureelements and spacer elements under elevated temperature and pressure.79. The method of claim 78, wherein said pressure is in excess ofapproximately 50 pounds per square inch and said temperature is inexcess of approximately 350 degrees Fahrenheit.
 80. The method of claim69, wherein said step of forming a plurality of arrays of first andsecond structural members comprises combining a plurality of layers ofcomposite fiber material.
 81. The method of claim 80, further comprisingcutting said layers of composite fiber material into discrete shapes.82. The method of claim 81, wherein said discrete shapes include beamelements.
 83. The method of claim 80, wherein step of forming aplurality of arrays of first and second structural members comprisesaligning fibers parallel to some beam elements.
 84. The method of claim80, wherein said step of forming a plurality of arrays of first andsecond structural elements comprises combining at least eight layers ofcomposite fiber material.
 85. The method of claim 83, wherein said stepof forming a plurality of arrays of first and second structural elementscomprises orienting said fibers relative to the longitudinal axis ofsaid structural members at zero degrees, zero degrees, plus 29 degrees,minus 29 degrees, minus 29 degrees, plus 29 degrees, zero degrees andzero degrees respectively for said eight layers.
 86. The method of claim85, wherein said fibers are carbon.
 87. The method of claim 86, whereinsaid fibers are approximately 0.002 inches in diameter.